DAVx⁵ is more that 11 years old! How long are you using it?
Did you know that you can easily (re-)setup DAVx5 via QR code by simply using this type of URL to automatically pre-fill the DAVx5 Login screen: davx5://user@server.example.com/path/ You will need an appropriate QR code scan app like Binary Eye. Read more here: Pro tip: save the QR code somewhere and whenever you want to re-setup simply scan it again ;-). Also great to help other not so tech savvy users by simply giving them a QR code!
Since Deutsche Telekom (t-online.de) discontinued their own Sync app for Android they are now recommending DAVx5, which is very cool :) We've made a quick guide video to help new people using DAVx5 with this service. If you know people that want to switch you can point them to: